Adjustable filter element



United States Patent inventor Appl. No. Filed Patented Assignee Jack S.Singleton Sparta, NJ.

May 23, 1968 Dec. 29, 1970 Fluid Dynamics Incorporated Morristown, NJ.

a corporation of New York Continuation of application Ser. No. 678,280,Oct. 18, 1967, now abandoned.

ADJUSTABLE FILTER ELEMENT 3 Claims, 4 Drawing Figs.

U.S.Cl 210/91, 210/351, 210/488 Int. Cl. B01d 27/00, B01d 29/22 Field 01Search 210/91,

References Cited UNlTED STATES PATENTS Simoneton Seavey 1 Kendrick....Wells Yelinek et al.. Pall et al. Schmidli Toth et al.

Primary Examiner-Samih N. Zaharna Attorneys-George D. Richards andThomas Cifelli, Jr.,

Cifelli and Behr 210/35OX 210/351 210/488X 210/492 210/91 210/506X2l0/492X 210/488 ABSTRACT: An adjustable filter element including aplurality of stacked compressible filter discs and a selectivelyadjustable loading plate for applying or releasing a columnar load uponthe discs to compress or loosen them for varying the filter rating ofthe filter element.

*PATENTEUUEBZQBYU V 3550.777

INVENTOR JACK S. SINGLETON ATTOR ADJUSTABLE FILTER ELEMENT Thisapplication is acontinuation of my copending application Ser. No.678,280, filed Oct. 18, 1967, now abandonedv This invention relates toan improved filter element and more particularly to a filter which maybe mariually selectively adjusted to change the effective pore sizethrough the filtering media.

Filter elements known to the prior .art are generally specified for useon the basis of two parameters, namely (1) their size including diameterand length, and (2) their filter rating which rating denotes theeffective pore size of the filtering media and indicates the particlesizeretentivity of the media. It is not uncommon for a given piping prpower system to require several filter elements having differentcharacteristics to bepositioned at various locations therein, eachfilter element being appropriately selected to filter a contaminant of agiven mean particle size. If however the gas or fluid passing throughthe system is found to include a contaminant of a different particlesize it would be necessary to substitute a properly rated filterelement. This obviously necessitates the high cost of purchasing and thestorage of a large number of variously rated filter elements. 1

When the usual filter elements are fully saturated with contaminantparticles and reduce the effective flow of the gas or fluid through thesystem it is the usual practice to clean the elements by back-flushingthe gas or fluid through the elements to loosen and drive out theretained particles. This back-flushing must be accomplished at arelatively high pressure in order to dislodge the particles from thepores of the filtering media.

Accordingly it is the primary object of my invention to provide anadjustable filter element which may be purchased on the basis of onlyone of the above-mentioned parameters, viz. size, and which may beconstructed simply and inexpensively in any desired length.

Another object of my invention is to provide an adjustable filterelement having a unique filtering media construction comprising stackedcompressible discs of a matted fibrous material. I

Still another object of my invention is to provide an adjustable filterelement which may be easily cleaned by increasing the pore size whileback-flushing the gas or fluid through the element.

The objects of my invention are accomplished inone form, by providing anadjustable filter element with a support assembly including a foraminoustubular support core and an annular filtering media comprising aplurality of stacked annular filter discs encircling the core. Thefilter element also includes a selectively axially movable loading plateat one end of I the filtering media being positioned to selectivelyapply and release an axial load to the filtering media to vary thefilter rating of the media and indicator means to readily select thedesired filter rating.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and further details ofthat which I believe to be novel and my invention will be clear from thefollowing description and claims taken with the accompanying drawingDESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference toFIG. 2 there is illustrated an adjustable filter element generallydenoted by the numeral through which a gas or fluid may pass in thedirection of the arrows, i.e. radially inwardly through the porouscylindrical wall 12 and axially outwardly through the lower end 14. The

filter element 10 includes an annular outlet fitting l6 positioned atits lower end having an upper planar support surface 18 and an innercylindrical wall 20. A circumferential relieved portion 22 defining ashoulder 24 and a groove 26 adapted to receive an O-ring or othersealing means when assembled with a suitable coupling member are formedin the wall 20. A foraminous cylindrical support core 28 is positionedwith its lower end within the relieved portion 22 adjacent the shoulder24. An upper end fitting 30 includes an axial adjusting post 32 formedwith a threaded portion 34 at its end and a cylindrical base portion 36formed with a circumferential relieved portion 38 defining a shoulder40. The base portion has an outer diameter of substantially the samedimension as the support core outer diameter, and the upper end fitting30 is positioned within the support core so that the upper rim of thesupport core abuts the shoulder 40. The outlet fitting 16, the supportcore 28 and the upper end fitting 30 are permanently secured together bywelds 42 or other suitable securing means and filter element and may bemade in any desired length to satisfy the requirements of the systeminto which it is placed. This is simply achieved in manufacture or onthe job by cutting the support core 28 to the length desired.

A lower bearing washer 44 made of a low friction material such asTeflon* (a trademark of Dupont) is positioned upon the support surface18 of the outlet fitting 16. The filter media of my adjustable filterelement comprises a plurality of annu-' lar filter discs 46 stacked uponthe lower bearing washer 44 and encircling the support core 28 from itslower end to its upper end. I

Each annular filter disc 46 (FIG. 3) comprises a central metal washer 48made of stainless steel or other suitable material to which is securedon both planar faces thereof a random array of filaments also preferablymade of stainless steel to form a resilient mat 50 upon each side of thewasher 48. The mats are permanently affixed to the metal washer by asintering process performed in a suitable heat treating furnace or theymay be adhered thereto with an adhesive such as an epoxy. When securedin place upon the metal washer 48 the free portion of the mats 50 remainresilient and loosely matted having a free unloaded dimension indicatedby the letter A as shown in FIG. 3. It should be understood'that thefree dimension A is indicative of a condition of maximum porosity of thefilter disc 46. The mats 50 are capable of being'selectively axiallycompressed to a minimum axial dimension indicated by the letter B inFIG. 4 in a manner to be fully described hereinafter. This dimension, ofcourse, corresponds to a condition of minimum porosity of the filterdisc 46.

An upper bearing washer 52 also madev of Tefion* is positioned upon thestack of filter discs 46 and encircles the support core 28 to which itmay be keyed in any known manner to be nonrotatable relative thereto.The adjustable filter element 10 of my invention is completed with thepositioning of a loading plate 54 upon the adjusting post 32. Theloading plate includes an axially extending portion 56 at one end havingan internally threaded portion 58 and being formed with an adjusting nut60 (see FIG. 1) on its outer surface. A groove 62 is defined therein forreceiving an O-ring 64 or-other suitable sealing means. The loadingplate further includes a radially outwardly extending flange 66 whichterminates in an annular axially extending loading wall 68 having aplanar loading surface 70. Calibration lines 72 are scored or otherwisemarked on the exterior surface of the loading wall 68 of loading plate54 and suitable indicia (not shown) are also marked thereon after thefilter has been calibrated. An indicator 74 fixedly secured to the upperbearing washer 52 or secured to the support core 28 completes theadjustable filter element 10.

Once assembled, the adjustable filter element must be calibrated inorder to apply the appropriate filter rating indicia adjacent the scoredcalibration lines 72. Calibration is accom plished by subjecting thefilter element 10 to a usual bubble point test over a range of possiblefilter ratings. Starting'with the filter discs in their loose (dimensionA) condition to determine the corresponding filter rating, the adjustingnut 60 is turned in a clockwise direction as viewed in FlG. 1 insuitable angular increments to compress the mats 50 for reducing theeffective pore size of the filtering media to the maximum loadingcorresponding to the dimension B condition In use, the user need merelyturn the adjusting nut 60 in the clockwise or counterclockwisedirections to the desired filter rating indicated by the indicator 74.

Another desirable feature of my adjustable filter elements is the easewith which they may be repeatedly recleaned. lt is merely necessary toloosen the adjusting nut 60 in order to loosen the entire filteringmedia to a point where the resilient mats 50 return to their porouscondition. By backfiushing through the porous filter media thecontaminating particles are easily driven therefrom. Alternatively it issimple to completely disassemble the element and then to clean eachfilter disc individually in a suitable solvent.

Having described my invention of an adjustable filter element it will bereadily appreciated by those skilled in this art that a filter elementemploying my invention is simple in design and ingenious in operation.It should be understood that the present disclosure has been made onlyby way of example and that numerous changes in details of constructionand the combination and arrangement of parts may be resorted to withoutdeparting from the true spirit and the scope ofthe invention ashereinafter claimed.

lclaim:

1. In an adjustable filter comprising a plurality of annular filterdiscs and a support assembly including first and second end fittings andan intermediate elongated foraminous core, and in which the filter discsare disposed in abutting relation and collectively encircle and extendsubstantially the entire length of said foraminous core, the improvementwhich comprises: said annular filter discs being axially compressibleand being retained on said foraminous core by said first end fitting, aloading member rotatably mounted on said second end fitting and having aloading surface positioned to apply axial pressure tosaid plurality ofabutting annularfilter discs, said loading member being adapted to moveaxially of said foraminous core in one direction on clockwise rotationand in the opposite axial direction on counterclockwise rotation, saidaxial movement of said loading member in one direction producing anincrease in the axial load on said filter discs and said axial movementof the loading member in the opposite direction causing a decrease inthe axial load on said filter discs, whereby the degree of compressionof said compressible filter discs and the filter rating of said filtercan be varied, and

indicating means for readily selecting the desired filter ratingincluding indicia defined upon said loading member and a)' cooperatingindicator mounted on said filter.

2. In an adjustable filter comprising a plurality of annular prises:said annular filter discs being axially compressible and being retainedon said foraminous core by said first end fitting, a loading memberrotatably mounted on said second end fitting and having a loadingsurface positioned to apply axial pressure to said plurality of abuttingannular filter discs, said loading member being adapted to move axiallyof said foraminous core in one direction on clockwise rotation and inthe opposite axial direction on counterclockwise rotation, said axialmovement of said loading member in one direction producing an increasein the axial load on said filter discs and said axial movement of theloading member in the opposite direction causing a decrease in the axialload on said filter discs, whereby the degree of compression of saidcompressible filter discs and the filter rating of said filter can bevaried, said first end fitting includes mounting means for receivingone. end of said foraminous core, an outlet port for said filter, and

means providing an annular support surface for retaining said filterdiscs on said core, said second end fitting includes mounting means forreceiving the other end of said core and an axial adjusting memberhaving a threaded portion, and said loading member has a threadedaperture for receiving and engaging in threaded relation the threadedportion of said second end fitting, indicating means for readilyselecting the desired filter rating including indicia defined upon saidloading member and a cooperating indicator mounted on said filter.

3. An adjustable filter according to claim 2 wherein each of

